Phiếu bài tập Hóa học cho kỳ thi đầu vào điều dưỡng có đáp án

What is the half-life of a radioactive isotope?

1. AThe time taken for half of the radioactive atoms in a sample to decay
2. BHalf the time it takes for all the atoms to decay
3. CThe time taken for the mass of a sample to double in size
4. DHalf the number of protons in the nucleus

What does the law of conservation of mass state?

1. AThe mass of products is always greater than the mass of reactants
2. BMass is lost as heat in every reaction
3. CGases have no mass
4. DMass is neither created nor destroyed in a chemical reaction

What is the SI base unit of mass?

1. AKilogram
2. BPound
3. CNewton
4. DGram

What is a polymer?

1. AAn ion with more than one charge
2. BA large molecule built from many repeating smaller units called monomers
3. CA small molecule containing only two atoms of one element
4. DA mixture of several different elements

Which bond joins amino acids together in a protein?

1. AA peptide bond
2. BA glycosidic bond
3. CA hydrogen bond
4. DAn ionic bond

Using significant figures, what is 2,5 cm × 3,42 cm?

1. A9 cm²
2. B8,55 cm²
3. C8,550 cm²
4. D8,6 cm²

An unknown element is shiny, conducts electricity, and reacts vigorously with water to form a basic solution and hydrogen gas. In which group is it most likely?

1. AGroup 14 (carbon group)
2. BGroup 1 (alkali metals)
3. CGroup 17 (halogens)
4. DGroup 18 (noble gases)

A piece of copper is placed in zinc sulfate solution. Zinc is more reactive than copper. What happens?

1. AZinc metal coats the copper and the solution turns blue
2. BNo reaction occurs
3. CCopper replaces zinc, forming copper sulfate
4. DHydrogen gas is produced